digitalmars.D.learn - -vgc Info ok?
- Chris (6/6) May 18 2015 The following
- ketmar (2/10) May 18 2015 it can throw "out of range" error, which is `new`ed.=
- Chris (8/19) May 18 2015 But shouldn't it read "accessing an associative array may cause
- ketmar (12/35) May 18 2015 not any access may cause allocation. `auto e =3D "key" in myarray;` will...
- Chris (10/52) May 19 2015 Yes, that's exactly what was driving at. Accessing is not
- anonymous (10/11) May 19 2015 Array access can also throw RangeError, but -vgc and @nogc don't
- ketmar (3/14) May 19 2015 hm. now either this is bug, or "-vgc" should not warn about AA access.=2...
- Namespace (3/9) May 19 2015 No error if you use myarray.get("key", null); or string* entry =
- Chris (2/13) May 19 2015 What are the advantages / disadvantages of the two methods?
- Namespace (3/17) May 19 2015 You could get null with "in" if your key is not there. Besides
- thedeemon (4/5) May 19 2015 Are you sure you understand "indexing" as we do? It's not like
The following string[string] myarray = ["key":"value"]; string entry; entry = myarray["key"]; // => vgc: indexing an associative array may cause GC allocation Why is _accessing_ an assoc treated as indexing it?
May 18 2015
On Mon, 18 May 2015 14:30:42 +0000, Chris wrote:The following =20 string[string] myarray =3D ["key":"value"]; string entry; entry =3D myarray["key"]; // =3D> vgc: indexing an associative array may cause GC allocation =20 Why is _accessing_ an assoc treated as indexing it?it can throw "out of range" error, which is `new`ed.=
May 18 2015
On Monday, 18 May 2015 at 14:34:38 UTC, ketmar wrote:On Mon, 18 May 2015 14:30:42 +0000, Chris wrote:But shouldn't it read "accessing an associative array may cause GC allocation"? And maybe a hint to the exception that may be thrown. It's not the same as myarray["key1] = "some value"; myarray["key2] = "some other value"; A bit confusing.The following string[string] myarray = ["key":"value"]; string entry; entry = myarray["key"]; // => vgc: indexing an associative array may cause GC allocation Why is _accessing_ an assoc treated as indexing it?it can throw "out of range" error, which is `new`ed.
May 18 2015
On Mon, 18 May 2015 14:41:19 +0000, Chris wrote:On Monday, 18 May 2015 at 14:34:38 UTC, ketmar wrote:yOn Mon, 18 May 2015 14:30:42 +0000, Chris wrote:The following =20 string[string] myarray =3D ["key":"value"]; string entry; entry =3D myarray["key"]; // =3D> vgc: indexing an associative array ma=not any access may cause allocation. `auto e =3D "key" in myarray;` will=20 not allocate, for example. yet it's still accessing the array. it's=20 *indexing* which may end in allocation.=20 But shouldn't it read "accessing an associative array may cause GC allocation"?cause GC allocation =20 Why is _accessing_ an assoc treated as indexing it?it can throw "out of range" error, which is `new`ed.And maybe a hint to the exception that may be thrown.i believe that such explanation is a work for lint-like tool. burden=20 compiler with special cases can lead too far. ;-)It's not the same as =20 myarray["key1] =3D "some value"; myarray["key2] =3D "some other value"; =20 A bit confusing.yes, it requires some knowledge of language and libraries. "-vgc" is not=20 a linter, though, it was made with some assumptions about user's=20 knowledge. yet you can open ER in bugzilla, maybe DMD developers will implement it.=20 i'm not a developer, and i can be wrong in reasons behind "-vgc".=
May 18 2015
"Chris" <wendlec tcd.ie> On Monday, 18 May 2015 at 18:40:15 UTC, ketmar wrote:On Mon, 18 May 2015 14:41:19 +0000, Chris wrote:Yes, that's exactly what was driving at. Accessing is not indexing, and yet I get a warning for _indexing_, while the real reason is that a wrong access can cause an exception (which allocates). I.e. it should be "accessing an associative array may cause GC allocation on error" Maybe the message with "indexing" for accessing is merely reusing the message for indexing, or all assoc array operations are lumped together as "indexing". I dunno. It seems wrong to me, because it's inaccurate.On Monday, 18 May 2015 at 14:34:38 UTC, ketmar wrote:not any access may cause allocation. `auto e = "key" in myarray;` will not allocate, for example. yet it's still accessing the array. it's *indexing* which may end in allocation.On Mon, 18 May 2015 14:30:42 +0000, Chris wrote:But shouldn't it read "accessing an associative array may cause GC allocation"?The following string[string] myarray = ["key":"value"]; string entry; entry = myarray["key"]; // => vgc: indexing an associative array may cause GC allocation Why is _accessing_ an assoc treated as indexing it?it can throw "out of range" error, which is `new`ed.And maybe a hint to the exception that may be thrown.i believe that such explanation is a work for lint-like tool. burden compiler with special cases can lead too far. ;-)It's not the same as myarray["key1] = "some value"; myarray["key2] = "some other value"; A bit confusing.yes, it requires some knowledge of language and libraries. "-vgc" is not a linter, though, it was made with some assumptions about user's knowledge. yet you can open ER in bugzilla, maybe DMD developers will implement it. i'm not a developer, and i can be wrong in reasons behind "-vgc".
May 19 2015
On Monday, 18 May 2015 at 14:34:38 UTC, ketmar wrote:it can throw "out of range" error, which is `new`ed.Array access can also throw RangeError, but -vgc and nogc don't mind that: ---- void main() nogc { int[] a; auto b = a[0]; } ----
May 19 2015
On Tue, 19 May 2015 13:17:15 +0000, anonymous wrote:On Monday, 18 May 2015 at 14:34:38 UTC, ketmar wrote:hm. now either this is bug, or "-vgc" should not warn about AA access.=20 will you fill an issue in bugzilla?=it can throw "out of range" error, which is `new`ed.=20 Array access can also throw RangeError, but -vgc and nogc don't mind that: ---- void main() nogc { int[] a; auto b =3D a[0]; } ----
May 19 2015
On Monday, 18 May 2015 at 14:30:43 UTC, Chris wrote:The following string[string] myarray = ["key":"value"]; string entry; entry = myarray["key"]; // => vgc: indexing an associative array may cause GC allocation Why is _accessing_ an assoc treated as indexing it?No error if you use myarray.get("key", null); or string* entry = "key" in myarray;
May 19 2015
On Tuesday, 19 May 2015 at 09:10:50 UTC, Namespace wrote:On Monday, 18 May 2015 at 14:30:43 UTC, Chris wrote:What are the advantages / disadvantages of the two methods?The following string[string] myarray = ["key":"value"]; string entry; entry = myarray["key"]; // => vgc: indexing an associative array may cause GC allocation Why is _accessing_ an assoc treated as indexing it?No error if you use myarray.get("key", null); or string* entry = "key" in myarray;
May 19 2015
On Tuesday, 19 May 2015 at 09:43:06 UTC, Chris wrote:On Tuesday, 19 May 2015 at 09:10:50 UTC, Namespace wrote:You could get null with "in" if your key is not there. Besides that, no disadvantages.On Monday, 18 May 2015 at 14:30:43 UTC, Chris wrote:What are the advantages / disadvantages of the two methods?The following string[string] myarray = ["key":"value"]; string entry; entry = myarray["key"]; // => vgc: indexing an associative array may cause GC allocation Why is _accessing_ an assoc treated as indexing it?No error if you use myarray.get("key", null); or string* entry = "key" in myarray;
May 19 2015
On Monday, 18 May 2015 at 14:30:43 UTC, Chris wrote:Why is _accessing_ an assoc treated as indexing it?Are you sure you understand "indexing" as we do? It's not like indexing of databases, it's just "accessing by index" i.e. using myarray[some_index].
May 19 2015
On Tuesday, 19 May 2015 at 11:08:52 UTC, thedeemon wrote:On Monday, 18 May 2015 at 14:30:43 UTC, Chris wrote:I understood indexing as assigning an index to something myarray["Index1"] = "First Entry"; As in https://en.wiktionary.org/wiki/indexing https://en.wiktionary.org/wiki/index#VerbWhy is _accessing_ an assoc treated as indexing it?Are you sure you understand "indexing" as we do? It's not like indexing of databases, it's just "accessing by index" i.e. using myarray[some_index].
May 19 2015
On Tue, 19 May 2015 11:36:32 +0000, Chris wrote:On Tuesday, 19 May 2015 at 11:08:52 UTC, thedeemon wrote:and that's wrong. ;-) most programmers in this case read "indexing" as=20 "accesing by index". it's a common term for such access. tbh, i didn't even understand you fully until i read the post i'm=20 answering to.=On Monday, 18 May 2015 at 14:30:43 UTC, Chris wrote:=20 I understood indexing as assigning an index to something =20 myarray["Index1"] =3D "First Entry"; =20 As in =20 https://en.wiktionary.org/wiki/indexing https://en.wiktionary.org/wiki/index#VerbWhy is _accessing_ an assoc treated as indexing it?Are you sure you understand "indexing" as we do? It's not like indexing of databases, it's just "accessing by index" i.e. using myarray[some_index].
May 19 2015
On Tuesday, 19 May 2015 at 12:41:29 UTC, ketmar wrote:On Tue, 19 May 2015 11:36:32 +0000, Chris wrote:Is that so. I don't remember having come across this meaning. It is usually called "access" or "indexing access" (cf. http://dlang.org/hash-map.html). I still think that saying just "indexing" is not correct in -vgc, since it can be both assignment and access.On Tuesday, 19 May 2015 at 11:08:52 UTC, thedeemon wrote:and that's wrong. ;-) most programmers in this case read "indexing" as "accesing by index". it's a common term for such access.On Monday, 18 May 2015 at 14:30:43 UTC, Chris wrote:I understood indexing as assigning an index to something myarray["Index1"] = "First Entry"; As in https://en.wiktionary.org/wiki/indexing https://en.wiktionary.org/wiki/index#VerbWhy is _accessing_ an assoc treated as indexing it?Are you sure you understand "indexing" as we do? It's not like indexing of databases, it's just "accessing by index" i.e. using myarray[some_index].tbh, i didn't even understand you fully until i read the post i'm answering to.
May 19 2015